ROTATING AIRFOIL FOR SUSTAINING LIFT AND METHOD FOR GENERATING LIFT
Described herein is a rotor blade assembly (100) and a method for generating a lift in a fluid installation. The rotor blade assembly includes an arcuate rotor blade (102) that is configured to be rotated about its axis Y. One or more motion transmitting members (106, 114, 116) are provided that connect the arcuate rotor blade with at least one power generating member (104) for transmitting torque from the arcuate rotor blade to the at least one power generating member (104). The fluid incident on the arcuate rotor blade is caused to flow over a first leading edge L1 of a rotor blade towards a central rib R of the rotor blade (102). This fluid flow is then caused to flow along the central rib R of the rotor blade towards a stem section of the rotor blade from where the fluid exits, thereby causing rotation of the rotor blade.
The present subject matter in general relates to airfoils and in particular relates to rotating airfoils for sustaining lift in rotors that are employed in diverse applications, such as energy generation and propulsion.
BACKGROUNDAirfoils are responsible for generating lift or drag in an object. When an airplane, propeller or turbine moves through a fluid, the airfoil in the blade or tail of the airplane or in the blade of the propeller or turbine produces the desired lifting force that acts perpendicular or parallel to the stream of fluid. Airfoils may be categorized as symmetrical airfoils, in which the curvatures of surfaces above and below the chord line are the same, and non-symmetrical airfoils in which curvatures of surfaces above and below the chord line are different.
Generally, rotating turbines and propellers are derived from NACA airfoils. However, such airfoils are designed to be suitable for straight and level flight, and do not address the issues of rotating objects. With the advancement in renewable energy installations including fluid turbine systems, such as wind and hydro turbine installations, it is important to improve performance of such installations by enhancing their rotor blade efficiency and at the same time overcoming challenges in operation, installation, and maintenance of such installations. Further, the surface features in traditional turbine blades are usually smooth, thereby resulting in compromised aerodynamic efficiency. Furthermore, propellers used for air and water travel, such as airplanes, ships, boats etc. require continuous improvement.
Therefore, there is a well felt need for an airfoil and associated turbines or propellers that overcome the above and other challenges faced in the industry due to drawbacks in conventional airfoils.
SUMMARYIt is an object of the present subject matter to provide a rotating airfoil for sustaining lift.
It is another object of the present subject matter to improve performance of energy generation systems and propulsion systems.
It is yet another object of the present subject matter to provide improved and cost-effective airfoil for propeller and/or turbine blades.
It is yet another object of the present subject matter to enhance rotational efficiency of rotating systems employed, for example, in fluid turbine systems comprising but not limited to wind and hydro turbine installations and in vehicles comprising but not limited to airplanes and ships.
It is yet another object of the present subject matter to enhance aerodynamic efficiency of rotating systems employed, for example, in fluid turbine systems comprising but not limited to wind and hydro turbine installations and in vehicles comprising but not limited to airplanes and ships.
It is yet another object of the present subject matter to enhance the overall efficiency of rotating systems employed, for example, in fluid turbine systems comprising but not limited to wind and hydro turbine installations and in vehicles comprising but not limited to airplanes and ships.
It is yet another object of the present subject matter to reduce installation and maintenance cost in a rotor-based system.
It is yet another object of the present subject matter to provide airfoils having autorotation and rapid fluid displacement as well as retardation feature.
It is yet another object of the present subject matter to provide airfoils that can be employed in vertical and/or horizontal fluid turbines.
It is yet another object of the present subject matter to provide airfoils that can be employed in propellers for air and water travel.
It is yet another object of the present subject matter to provide airfoils that address challenges involved with rotating objects such as rotor blades and propellers.
It is yet another object of the present subject matter to reduce the drag generated during operation of rotor blades.
It is yet another object of present subject matter to increase surface drag to induce vortical airflow to cause the airfoil to lift.
The present subject matter provides an airfoil that can be employed for energy generation and/or propulsion. The airfoil according to the present invention is most suitable for rotating systems comprising but not limited to turbines and/or propeller blades. In a preferred embodiment, the airfoil of the present subject matter comprises a rotating airfoil for use in vertical or horizontal wind or other fluid turbines. The rotating airfoil is configured to be employed in generating mechanical power that can be converted into other power sources like compressed air or electrical power. Alternatively, the airfoils according to the present subject matter can be used in driving and/or driven propeller blades of propulsion applications. The present airfoils can be advantageously used in blade profiles of rotors that are used as a propeller for air and water/sea travel.
The present subject matter relates to a rotor blade assembly for generating a lift in a fluid installation, the rotor blade assembly comprising an arcuate rotor blade configured to be rotated about its axis; and at least one motion transmitting member connecting the arcuate rotor blade with at least one power generating member for transmitting torque from the arcuate rotor blade to the at least one power generating member.
In an embodiment, the rotor blade comprises a concave surface that is the working surface of the rotor blade and a convex surface with which the at least one motion transmitting member is connected.
In another embodiment, the rotor blade comprises a substantially arcuate configuration extending from a stem section to a tip section.
In yet another embodiment, the rotor blade comprises a central rib that separates the working surface of the rotor blade into a first side or Left-Hand Side and a second side or Right-Hand Side.
In yet another embodiment, the at least one motion transmitting member comprises at least one rotatable main shaft connecting the convex surface of the rotor blade with the at least one power generating member, and one or more supplementary shafts connecting the convex surface of the rotor blade with the at least one rotatable main shaft.
In yet another embodiment, the at least one motion transmitting member is attached at the point of intersection of a first section and a second section of the rotor blade.
In yet another embodiment, the first section comprises about 34% of the arcuate length of the rotor blade extending from the stem section and the second section comprises about 66% of the arcuate length of the rotor blade extending from the tip section.
In yet another embodiment, the rotor blade assembly further comprises a plurality of veins throughout the concave surface and the convex surface of the rotor blade.
In yet another embodiment, the widest section W of the rotor blade is provided at about 34% distance from the stem section of the rotor blade.
In yet another embodiment, the rotor blade comprises a plurality of leading edges and a plurality of trailing edges such that the first leading edge and the first trailing edge are formed in the second section of the rotor blade, and the second leading edge and the second trailing edge are formed in the first section of the rotor blade.
In yet another embodiment, a camber angle of the right-hand side of the rotor blade is greater that a camber angle of the left-hand side of the rotor blade.
A fluid turbine assembly is also provided that comprises the rotor blade assembly aligned axially with a Darrieus Turbine, wherein the rotor blade assembly forms the inner rotor, and the Darrieus Turbine forms the outer rotor.
Further, a multi-rotor fluid turbine assembly is provided that comprises a plurality of rotor blade assemblies mounted on a support plate, said support plate being connected with the at least one power generating member for transmitting torque to the at least one power generating member.
The present subject matter also provides a multi-turbine power generation system comprising a plurality of fluid turbines, each fluid turbine comprising the rotor blade assembly.
Furthermore, the present subject matter provides a method of generating a lift in a fluid installation, the method comprising the steps of causing the fluid to flow over a first leading edge L1 of a rotor blade towards a central rib of the rotor blade; causing the fluid to flow along the central rib of the rotor blade towards a stem section of the rotor blade; and causing the fluid to exit through the stem section of the rotor blade, thereby causing rotation of the rotor blade.
Numerous additional features, embodiments, and benefits of the methods and apparatus of the present invention are discussed below in the detailed description which follows.
The present invention, both as to its organization and manner of operation, together with further objects and advantages, may best be understood by reference to the following description, taken in connection with the accompanying drawings. These and other details of the present invention will be described in connection with the accompanying drawings, which are furnished only by way of illustration and not in limitation of the invention, and in which drawings:
The following presents a detailed description of various embodiments of the present subject matter with reference to the accompanying drawings.
The embodiments of the present subject matter are described in detail with reference to the accompanying drawings. However, the present subject matter is not limited to these embodiments which are only provided to explain more clearly the present subject matter to a person skilled in the art of the present disclosure. In the accompanying drawings, like reference numerals are used to indicate like components.
The specification may refer to “an”, “one”, “different” or “some” embodiment(s) in several locations. This does not necessarily imply that each such reference is to the same embodiment(s), or that the feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments.
As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless expressly stated otherwise. It will be further understood that the terms “includes”, “comprises”, “including” and/or “comprising” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being “attached” or “connected” or “coupled” or “mounted” to another element, it can be directly attached or connected or coupled to the other element or intervening elements may be present. As used herein, the term “and/or” includes any and all combinations and arrangements of one or more of the associated listed items.
The figures depict a simplified structure only showing some elements and functional entities, all being logical units whose implementation may differ from what is shown.
Rotors determine efficiency and performance of a rotating system. The present invention provides a solution to improve the rotational efficiency, aerodynamic efficiency, and overall efficiency of rotating systems. The present invention also provides a method for generating a lift in applications including but not restricted to vertical and/or horizontal axis wind and/or other fluid turbines, such as hydro turbines, and propellers employed for air and water travel, such as airplanes, ships, boats etc. Typically, for an un-ducted turbine, the efficiency is bound by Betz limit. The rotating airfoils according to the present subject matter are configured to sustain lift in an efficient manner. Further, the proposed airfoils provide autorotation and rapid fluid displacement and retardation. The addition of surface roughness in the form of veins creates a boundary layer for the blade and affect the aerodynamic efficiency of the rotor by creating a subtle layer of disturbed fluid on the surface so that the moving fluid does not directly interact with the blade surface which would otherwise increase drag. In other words, a local drag is created due to the presence of surface roughness.
The airfoils according to the present invention can be applied in vertical and/or horizontal axis wind and/or other fluid turbines, such as hydro turbines. In an embodiment, the proposed airfoils are configured to be used for generating mechanical power that can be converted into other power sources like compressed air or electrical power. However, the scope of the present invention is not limited to wind and/or fluid turbine applications. Alternatively, the rotor with blade profile employing the present airfoil can be employed as a propeller for air and underwater/sub-sea travel. Similarly, the present airfoil can also be applied to other applications where desired lift is required. In a preferred embodiment, any number of blades comprising the present airfoil can be employed in a system. In yet another preferred embodiment, a rotor blade comprising the present airfoil can be angled in any direction with respect to the flow in a 3-dimensional space.
The airfoil in accordance with a preferred embodiment of the present invention comprises a monofoil that readily autorotates and provides a continuous as well as asymmetric blade profile.
In a preferred embodiment, the motion transmitting member comprises at least one main shaft 106 for transmitting rotary motion or torque from the rotor blade 102 to the generator 104 and at the same time for supporting the rotor blade 102 in the rotor blade assembly 100, as shown in
The embodiment explained in
In an embodiment, the main shaft 106 may comprise a single straight segment without any angular segment, as shown in
In the embodiments explained above, the rotor blade 102 is configured to rotate about its axis Y in anticlockwise direction X. However, it is made clear that the rotor blade 102 may rotate in clockwise direction without deviating from the scope of the present subject matter. Therefore, the rotor blade 102 and hence the main shaft 106 are configured to rotate either in clockwise direction or in anti-clockwise direction. The direction of rotation of the rotor blade 102 depends upon the direction of flow of fluid. In yet another embodiment, the rotor blade 102 is configured to rotate both in clockwise direction and in anticlockwise direction depending upon the motion of the stream in a fluid installation system without deviating from the scope of the present subject matter. In such embodiment, both the motion of the fluid stream and the orientation of the rotor blade or airfoil would have to be changed to alter the direction of rotation. Once the parameters are fixed, the turbine would rotate in the same direction and the generator poles would not need to be changed for a change in flow direction of the fluid. In any of the given configurations, no yawing mechanism is required for the operation in the real environment.
In the embodiments depicted
The rotor blade assembly 100 according to a preferred embodiment is configured to be employed in a multitude of applications including but not limited to turbines of wind and hydro turbine installations as well as propellers for applications in air and water travel. In a preferred embodiment, as shown in
The configuration of the rotor blade 102, in a preferred embodiment, is shown in
According to the preferred embodiments described above, the rotational motion or torque from the rotor blade 102 is transferred to the generator 104 with the help of the rotatable main shaft 106 and optionally one or more supplementary shafts 114, 116, as shown in
In a preferred embodiment, one end of the main shaft 106 is attached to the central rib R. The positioning of the main shaft 106 is such that when the force is exerted by the surrounding fluid on the concave surface 122, i.e., the working surface, of the rotor blade 102, the rotor blade 102 rotates about the axis of rotation Y. This enables rotation of the main shaft 106 about its axis Y to transmit the rotational motion or torque to the generator 104 for generating the desired output. The continuous exertion of force by surrounding fluid on the working surface 122 of the rotor blade 102 ensures continuous rotation of the rotor blade 102, thereby ensuring continuous output generation by the generator 104. In an embodiment, the main shaft 106 may be attached at the center of the arcuate length of the central rib R.
During rotation, the central rib R dips along with the second section S2 of the rotor blade 102 and diverges to the remainder of the rotor blade 102 on one side and the load bearing main shaft 106 on the other. The remainder of the airfoil, i.e., the first section S1 twists inwards, i.e., towards Right-Hand Side (RHS) of the rotor blade 102. This is also the direction of rotation of the rotor blade 102.
According to a preferred embodiment of the present subject matter, the rotor blade 102 comprises a single continuous structure that is formed around the central rib R, as shown in
In a preferred embodiment, the rotor blade 102 comprises a plurality of veins V throughout the concave surface 122 of the rotor blade 102. The plurality of veins V provide roughness on the concave surface 122 of the rotor blade 102 that aids in creating a boundary layer near the surface, thereby improving efficiency of the rotor blade. Moreover, veins V add to the structural strength of the rotor blade 102. In an embodiment, a dense web of veins V spreading throughout the concave surface 122 of the rotor blade 102. In another embodiment, the veins V are provided both on the concave surface 122 as well as on the convex surface 124 of the rotor blade 102, as shown in
In a preferred embodiment, the dimensions of the rotor blade assembly 100 according to the present subject matter are as follows:
-
- Total arcuate length of the rotor blade 102 from stem section 118 to tip section 120=about 255 mm
- Total arcuate length of the extended portion R1=about 26 mm
- Total arcuate length of first section S1=about 86 mm
- Total arcuate length of second section S2=about 169 mm
- Total arcuate length of third section S3=about 131 mm
- Ratio S1:S2=about 0.50
- Ratio S1:S3=about 0.65
- Ratio S1+S3:S1+S2=about 0.85
The flow of fluid over the working surface 122 of the rotor blade 102 is depicted by arrows F1, F2 and F3 in
As can be seen in
The first leading edge L1 causes the fluid to flow towards the central rib R from the first leading edge L1, as shown by arrows F1 in
Both the rotor blade assembly 100 and the Darrieus Turbine 202 of the fluid turbine assembly 200 are configured to together, but independently of each other, transfer torque to the generator encompassed in a water-tight generator casing 204 for power generation. In the embodiment depicted in Figures H and 12, the generator casing 204 encompassing the generator is placed below the assembly of the rotor blade assembly 100 and the Darrieus Turbine 202. However, in another embodiment, the generator casing 204 encompassing the generator can be placed above the assembly of the rotor blade assembly 100 and the Darrieus Turbine 202, as shown in
In the embodiment depicted in
While the preferred embodiments of the present invention have been described hereinabove, it should be understood that various changes, adaptations, and modifications may be made therein without departing from the spirit of the invention and the scope of the appended claims. It will be obvious to a person skilled in the art that the present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive.
Claims
1. A rotor blade assembly for generating a lift in a fluid installation, the rotor blade assembly comprising
- an arcuate rotor blade configured to be rotated about its axis Y; and
- at least one motion transmitting member connecting the arcuate rotor blade with at least one power generating member for transmitting torque from the arcuate rotor blade to the at least one power generating member.
2. The rotor blade assembly as claimed in claim 1, wherein the rotor blade comprises a concave surface that is the working surface of the rotor blade and a convex surface with which the at least one motion transmitting member is connected.
3. The rotor blade assembly as claimed in claim 1, wherein the rotor blade comprises a substantially arcuate configuration extending from a stem section to a tip section.
4. The rotor blade assembly as claimed in claim 1, wherein the rotor blade comprises a central rib R that separates the working surface of the rotor blade into a first side or Left-Hand Side LHS and a second side or Right-Hand Side RHS.
5. The rotor blade assembly as claimed in claim 1, wherein the at least one motion transmitting member comprises at least one rotatable main shaft connecting the convex surface of the rotor blade with the at least one power generating member, and one or more supplementary shafts connecting the convex surface of the rotor blade with the at least one rotatable main shaft.
6. The rotor blade assembly as claimed in claim 1, wherein the at least one motion transmitting member is attached at the point of intersection of a first section S1 and a second section S2 of the rotor blade.
7. The rotor blade assembly as claimed in claim 6, wherein the first section S1 comprises about 34% of the arcuate length of the rotor blade extending from the stem section and the second section S2 comprises about 66% of the arcuate length of the rotor blade extending from the tip section.
8. The rotor blade assembly as claimed in claim 1 further comprises a plurality of veins V throughout the concave surface and the convex surface of the rotor blade.
9. The rotor blade assembly as claimed in claim 1, wherein the widest section W of the rotor blade is provided at about 34% distance from the stem section of the rotor blade.
10. The rotor blade assembly as claimed in claim 1, wherein the rotor blade comprises a plurality of leading edges L1, L2 and a plurality of trailing edges T1, T2 such that the first leading edge L1 and the first trailing edge T1 are formed in the second section S2 of the rotor blade, and the second leading edge L2 and the second trailing edge T2 are formed in the first section S1 of the rotor blade.
11. The rotor blade assembly as claimed in claim 1, wherein a camber angle C1 of the right-hand side RHS of the rotor blade is greater that a camber angle C2 of the left-hand side LHS of the rotor blade.
12. A fluid turbine assembly comprising the rotor blade assembly as claimed in claim 1 aligned axially with a Darrieus Turbine, wherein the rotor blade assembly forms the inner rotor, and the Darrieus Turbine forms the outer rotor.
13. A multi-rotor fluid turbine assembly comprising a plurality of rotor blade assemblies as claimed in claim 1 mounted on a support plate, said support plate being connected with the at least one power generating member for transmitting torque to the at least one power generating member.
14. A multi-turbine power generation system comprising a plurality of fluid turbines, each fluid turbine comprising a rotor blade assembly as claimed in claim 1.
15. A method of generating a lift in a fluid installation, the method comprising:
- causing the fluid to flow over a first leading edge L1 of a rotor blade 102 towards a central rib R of the rotor blade;
- causing the fluid to flow along the central rib R of the rotor blade 102 towards a stem section of the rotor blade; and
- causing the fluid to exit through the stem section of the rotor blade, thereby causing rotation of the rotor blade.
Type: Application
Filed: Jan 17, 2022
Publication Date: Feb 29, 2024
Inventor: Swati MAINI (Maharashtra, Mumbai)
Application Number: 18/261,691